Solar 101: How It Works

How Does Solar Power Work?

Solar technology is highly technical. To make an informed decision about whether solar power is right for your home, it’s important to understand the basic mechanisms behind solar electricity. Don’t worry, you won't need to become an engineer to purchase and maintain a solar panel system for your home. We’ll take care of the hard work of customizing a design that is appropriate for your home's unique characteristics and installing your solar panel system. An everyday residential solar system is simple to operate and maintain once we’ve designed and installed it. Here, we break down the components of solar energy for you and briefly explain how residential solar power installations work from solar panels to microinverters. Baker Electric Home Energy will get your solar power questions answered.

What Does Solar PV Stand For?

Solar PV is one of the most common solar technologies. In solar PV systems, electricity generated from solar panels relies on a process called photovoltaics, or PV for short. The process of converting energy produced by the sun into electricity utilizes a different process that happens naturally in certain types of material with electric characteristics called semiconductors. Voltage is created in semiconductors as they are exposed to photons (elementary particles of light). The result is called the PV effect, which represents the physical process of converting sunlight into energy. There are two forms of solar PV systems: crystalline silicon panels, which are typically used in home installations, and the less common thin film strips. PV technology can power a variety of electronic systems big and small, from a calculator to your home to a large business.

Solar PV technology was born in the U.S. in 1954 when researchers Daryl Chapin, Calvin Fuller and Gerald Pearson developed the silicon photovoltaic cell at Bell Labs, headquartered in New Jersey. Their invention was the first solar PV energy cell that could convert enough of the sun’s energy into power to run everyday electrical equipment. Early solar technologies that powered small electronics lead in the following decades to the solar PV panels that we use today. 

In response to the energy crisis of the 1970s, Congress enacted the Energy Tax Act to encourage homeowners to invest in solar technology. Tax credits for solar panel use were phased out by the mid-1980s, but they resurface today in the form of significant federal solar Investment Tax Credit for homeowners or businesses that purchase solar panels in San Diego or other cities in Southern California.

As solar panel technology improved, the manufacturing of PV panels became more practical, which prompted increases in production and falling prices. 

How Your Home Solar Power System Works

Your home solar system includes four primary pieces of equipment:

Solar panels | String inverter or microinverters | Roof mounts and racking | Monitoring system

Solar panels capture the sun’s rays and generate direct current (DC) power. That power is fed into a piece of equipment called an inverter. The inverter converts the DC power to alternating current (AC), which is the type of power your home can use. This AC power converted from the inverter is then fed to the home's main panel. What electricity your home doesn't use in that moment is distributed onto the grid. Your meter will register the excess electricity produced by the solar installation with the utility company per your net metering agreement to credit your account. Your meter will then eat into that credit at night and on shady days when your system is not producing. 

What is Net Energy Metering? 

Net Energy Metering is the billing mechanism the utility company uses for solar customers. It’s a simple concept: Power created from your home solar system is connected to the electric grid and credited in real time. Any excess power created by a residential solar system that’s not used at the moment is fed back into the power grid to be distributed by the utility. As this excess power is “back-fed,” your meter operates in reverse and you are credited for the extra electricity generated. As your home’s solar production offsets your energy consumption, you generate credits with the utility. Your electric bill is reduced as your traditional electric costs are eliminated. 

This give-and-take process occurs over the course of a year. Each year, you have a “true-up,” or reconciliation with the utility company to pay for any electricity that you used in excess of your solar power generation and credits. In the event that you generated more electricity than you used, the utility will pay you the wholesale value of the kilowatt-hours, which is about $0.04/kWh. 

In the spring of 2016, a new agreement of net metering, NEM 2.0, went into effect for all new San Diego Gas and Electric (SDG&E) solar customers. While the differences between NEM 1.0 and NEM 2.0 are nominal, some changes to the program became effective:

  • NEM 2.0 customers with onsite generation systems of less than 1.0 MW will now be required to pay “a reasonable fee” for interconnection, based on the utility company’s actual costs for these interconnections.
  • NEM 2.0 customers are required to pay non-bypassable charges (NBCs) for all energy they consume from the grid (in each metered interval). NBCs cannot be offset by energy exported to the grid.
  • NEM 2.0 customers will be required to prove on their NEM applications that major solar PV system components are CEC-approved and that they have at least a 10-year warranty on all equipment and the installation of that equipment.
  • NEM 2.0 introduced Time of Use (TOU) to residential customers. TOU will be mandatory for SCE and PGE customers under NEM 2.0. SDG&E customers will stay on tiered rates until five years after TOU rates are approved, likely to occur in 2017. After five years, they will adopt the TOU rate structure for NEM 2.0.

What You Need to Know About Solar Panels

Solar panels or “modules” are rated by their total output in watts and, depending on brand, can range from 200 to 350 watts. Modules also have an efficiency rating, which determines the size and total output of a solar panel. For example, a 10% efficient 275-watt module would be twice the physical size of a 20% efficient 275-watt module. Baker Electric Home Energy is an Elite SunPower Dealer and carries SunPower’s 345-watt solar panels.

Solar cells in PV modules are either monocrystalline silicon (c-Si) or polycrystalline silicon/multi-crystalline silicon (poly-Si or mc-Si). Monocrystalline silicon offers a sleek, continuous coloring because they are cut from a single piece of silicon ingot. They are more efficient than polycrystalline silicon cells. Poly-Si cells are less expensive but less efficient than monocrystalline cells.

Solar Monitoring

Every solar power system we design and install includes a unique monitoring system that quickly and easily determines daily, weekly, monthly and yearly solar energy production through web access and sometimes mobile applications. This detailed monitoring provides evidence that your investment in solar panels for your home is generating the financial benefit you expect.

Depending on the way in which your system is designed by one of our skilled Solar Energy Consultants, your home solar panel system will include one of four monitoring systems:

  • SunPower
  • Locus Energy
  • Enphase Envoy
  • SolarEdge

Some of these solar monitoring services offer module-level monitoring, allowing a homeowner to see the exact output of each solar panel for your home. Others offer a general generation report. If you decide to lease your solar panel equipment through SunPower, monitoring plays a big role since a lease agreement includes a production guarantee.